The Way Of AC And DC Transmitting Simultaneously Along The Same Feeder Line In Distribution Network

Stratagem for sustainable development of human being and advantages of distributed sources stir up much concentration on distributed generation (DG). DG can exert its superiority better and develop more greatly only when it is incorporated into power network. For distributed DC sources, there are two ways to get connected to the power grid. One of which is to convert the DC power to industrial frequency AC power and then connect the power grid in parallel; the other is to let the DC power transmitted through HVDC Light lines to the consumer side and then convert the DC power to the needed forms vary with the loads. The former have much negative influence to distribution network in operation and control aspects, while the latter needs to construct new transmission lines and also take transmission aisles. These two ways will surely play a great role in the rapid development of new-style distributed sources. But these are not enough, and new parallel connection operation ways are necessary to study on as the supplement of existent ways to jointly boost the development of distributed sources.Aiming at large-scale being of distribution network and low-capacity but large-quantity in a lot very long term of distributed sources, a new tentative plan of AC and DC transmitting simultaneously in the same feeder line in distribution network is presented, which provide a new approach of incorporating DG into power network. Analyzes the steady-state and transient characteristics based on the specific actualize form of this transmitting way, and analyzes its feasibility from the technique respect at the same time.Firstly, the basal idea and rationale of AC and DC transmitting simultaneously in the same feeder line are demonstrated detailedly, the circuit topology and correlative primary devices are given and illuminated as well. Aiming at low-capacity in a lot very long term of distributed sources, a strategy of considering DC distributed sources as constant power module when they are connected to the power grid and corresponding analytical model is proposed.Secondly, the influence on the environment and power equipments of DC earth return operation system based on the earth-injected DC current estimated is discussed. And the result is compared to that of HVDC earth return operation system and...